Shaped Brooms for Sweeping Concrete Curbs and Gutters

ABSTRACT

A broom has a rigid backing plate having a rectangular cross section, an overall length, an upper surface and an undersurface, the backing plate having two straight regions connected by a curved region, a bristle unit comprising an elastic and flexible backing having a rectangular cross section with a width and length the same as the backing plate, an upper surface and an undersurface, with bristles extending orthogonally from all of the undersurface of the bristle unit, providing a brushing surface at the end of the bristles away from the backing plate, and a handle connected by a connector mechanism to a point on the upper surface of the shaped rigid backing plate. The upper surface of the bristle unit is joined to the undersurface of the backing plate by an adhesive along the full length of the undersurface of the backing plate.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of co-pending application Ser. No. 17/196,702 filed Mar. 9, 2021, which claims priority to provisional patent application 63/124,952, filed Dec. 14, 2020. All disclosure of the parent applications is incorporated at least by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention is in the technical area of tools used in concrete construction for roads and curbs and pertains more particularly to brooms shaped in the curvature of curbs and gutters.

2. Description of Related Art

Concrete curb manufacture and placement is well-known in the construction arts. Placement and finishing of curbs and gutters is a common operation in road building and road maintenance. In the processes of road building, it is typical that a surface for a new road may be graded, base layers implemented, and pavement finished, then curbs and gutters, if required, are placed in sections, and sections are adhered to each other and to pavement surface by application of, for example, fresh concrete. In a final operation it is also typical that members of a road crew may finish a job by brushing the curb and gutter surfaces with hand-held brooms. It is also known to finish with machines that do the brushing, but it is almost always the case that members of a road crew will do manual brushing as well.

There are a variety of lateral cross section shapes for curbs and gutters in the art, and the number of workers in a road crew dedicated to finishing work, and the time and effort expended, is often extensive, because several passes need be made to be sure that all areal regions of a curb or gutter are properly brushed.

What is clearly needed are brushed formed in the lateral cross section shapes of curbs and gutters, allowing a member of a finishing crew to brush all or most of the areas of a curb or gutter in a single operation.

BRIEF SUMMARY OF THE INVENTION

A broom for brushing a curb is provided, comprising a rigid backing plate having a width, an overall length, an upper surface and an undersurface, bristles extending orthogonally from the undersurface of the backing plate, providing a brushing surface at the end of the bristles away from the backing plate, and a handle connected by a connector mechanism to a point on the upper surface of the backing plate. The curb to be brushed has a specific shape in lateral cross section that is other than a straight line, and the broom has a backing plate shaped such that the brushing surface conforms to a portion of the specific shape of the of the lateral cross section of the curb.

In one embodiment the specific shape of the lateral cross section of the curb comprises at least one straight region and at least one curved region. Also in one embodiment the rigid backing plate is formed from a straight plate of heat-sensitive polymer by heating regions to be curved, bending the straight plate at regions to be curved, and allowing the plate to cool and revert to rigidity. In one embodiment the rigid backing plate is formed from a straight plate of metal and bending the straight plate at regions to be curved. And in one embodiment the broom has three straight regions and two curved regions.

In one embodiment the broom has straight broom sections fastened to the undersurface of the rigid backing plate by conventional fasteners. Also, in one embodiment a length of a bristle assembly comprising bristles extending from a flexible and rubber-like panel having the width and length of the backing plate is joined to the underside of the backing plate by an adhesive. In one embodiment the connector mechanism is adjustable to vary the angle of extension of the connected handle relative to the backing plate. And in one embodiment the broom has bristle assemblies with bristles extending from a flexible and rubber-like panel having the width of the backing plate are provided with different bristle density, wherein bristle assemblies of different density are joined to different regions of the underside of the backing plate to provide a common bristle density at the brushing surface.

In another aspect of the invention a method for making a broom having a length and a width with a lengthwise curved shape is provided, comprising preparing a backing plate of the length and width with an upper surface and a lower surface, adding bristles to the undersurface of the backing plate, and forming the plate to the curved shape.

In one embodiment of the method the backing plate is a heat-formable polymer, the method comprising heating the backing plate at specific regions, forming the plate to the curved shape and cooling the plate to be rigid again. Also, in one embodiment the backing plate is metal, and the method comprises comprising bending the metal backing plate at specific regions around bending fixtures. Also, in one embodiment the method comprises providing a bristle assembly with bristles extending orthogonally from an underside of the flexible, rubber-like material having the width and length of the backing plate, bending the backing plate to the lengthwise curved shape, and joining the bristle assembly to the underside of the backing plate by a suitable adhesive.

In one embodiment of the method bristle assemblies of different bristle density are provided, and the method comprises joining bristle assemblies of different density to different regions of the underside of the backing plate. In one embodiment the method further comprises joining a handle connector to the upper surface of the backing plate. And in one embodiment the method comprises connecting a handle to the backing plate by the handle connector.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A through IF are cross section shapes of curbs and gutters in the art.

FIG. 2 is a perspective view of a brush according to an embodiment of the present invention.

FIG. 3A is an elevation view of a lateral section of a curb and gutter in an embodiment of the invention.

FIG. 3B is an elevation view of a shaped brush shown in close proximity to the curb and gutter of FIG. 3A in an embodiment of the invention.

FIG. 4A is a perspective view of a rigid backing plate for a broom in an embodiment of the invention.

FIG. 4B is a perspective view of a flexible bristle section in an embodiment of the invention.

FIG. 5 is an elevation view illustrating a process of making a broom head in an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A through 1F are cross section shapes of curbs and gutters in the art. FIG. 1A illustrates a low-profile curb 101 on a finished grade of street pavement 102. FIG. 1B illustrates another, higher profile curb 103 on pavement 104. FIG. 1C illustrates a curb and gutter section 105 on pavement 106. FIG. 1D illustrates a curb and gutter section termed a standard roll curb in the art. FIG. 1E illustrates one version of what is termed a cross gutter in the art, and FIG. 1F illustrates another type and shape for a cross gutter.

The shapes shown are but a few of many more shapes and sizes of curbs and gutters that may be implemented in the road construction art. In the current art manual brushes with straight crossbars of a variety of lengths, very similar to conventional push brooms are used. Considering curb and gutter instance FIG. 1C, for example, there are five areas, (a) through (e) that must be brushed. To properly brush and finish all the area of this curb and gutter, brushes of different lengths may have to be used, and certainly a considerable number of brush strokes would have to be made. In addition, areas of tis shape that are intersections or areas may not get properly brushed at all. And to keep up with a work schedule, several workers may be needed with different brushes to follow along and do the brushing and finishing.

FIG. 2 is an illustration of a shaped brush 201 in an embodiment of the present invention. Brush 201 has a long handle 202 for a construction finisher to use to manipulate brush 201 to brush concrete curbs and gutters. Handle 202 may be made of wood or of any other suitable material, such as plastic or metal, and may in some embodiments be telescoping for length adjustment or may have separate sections to screw together for the same purpose. Handles in embodiments of the invention may also have surface treatments or coverings to provide enhanced gripping characteristics.

Handle 202 connects to a shaped metal backing plate 204 by a pivoting connector 203. In this embodiment three separate straight brushes 207, 209 and 211, each having wooden bases 206, 208 and 210 respectively, are mounted to backing plate 204 by conventional fasteners represented by hex screws 205. Connector 203 is adapted to pivot in at least two degrees of freedom so that the relationship of handle 202 to the brush assembly may be optimized. FIG. 2 is meant to represent implementations of the invention wherein existing brushes or portions of existing brushes may be used to make curved brushes according to implementations of the instant invention.

In another version of the invention curved brushes may be manufactured with continuous curvature by adhering bristles to a curved plate. FIG. 3B is a view of curb and gutter 105 of FIG. 1C with a shaped brush 301 shown in FIG. 3A above the concrete curb and gutter, in an embodiment of the invention. The curb and gutter and the shaped brush in FIGS. 3A and 3B is an example of a situation that may be considered extreme. Most curbs and matching curved brushes in embodiments of the invention will not be as complicated as that shown in FIGS. 3A and 3B.

In FIG. 3A shaped brush 301 is shown in a side view, as is the curb and gutter 105. The skilled person will understand that the shaped brush has a width (into the plane of the figure) that may be a few inches, similar to the width of the brush in FIG. 2 , or to a conventional push broom. Shaped brush 301 has a rigid backing plate 302 and a region of bristles 304. The region of bristles extends along the full length of backing plate 302 along all of the straight portions and around the curved portions, whether the curves are inside or outside curves. There is along one straight portion a connector mechanism 303 adapted to connect backing plate 302 to a handle apparatus, similar to that shown and described with reference to FIG. 2 . A connector mechanism may be implemented on other portions of backing plate 302 as well.

The bristle regions of brush 304 have bristles of a length such that the inside shape of the brush matches the outside shape of curb and gutter 105. Brush 301 may be lowered over curb and gutter 105, and bristles will then contact all of the surfaces of the curb and gutter. Translating brush 301 in contact with the curb and gutter along a length of the curb and gutter will brush the surfaces in a finishing operation. In embodiments of the invention it is not necessary, however, that a curved brush contact all surfaces of a curb and gutter. In some circumstances a curved brush according to an embodiment of the invention may contact just two adjacent regions. For example, it may be seen that in FIGS. 3A and 3B straight regions of curb and gutter 105 are labeled (a), (b), (c), (d) and (e). A curved brush according to an embodiment of the invention might well be formed to make bristle contact with just regions (b), (c) and (d). So, in some embodiments a brush may be implemented of an overall length and of a shape that when in contact with curb and gutter 105 only a portion of the curb and gutter may be contacted, such as, for example, areas (d) and (e) and the curved region joining areas (d) and (e). Other shaped brushed may be implemented for brushing other adjacent areas and regions of the curb and gutter.

FIGS. 4A and 4B illustrate a method of constructing shaped brush 301 of FIG. 3 , or brushes of any other length and shape in embodiments of the invention. FIG. 4A shows a rigid backing plate 302 of length 1 and width w. In this example plate 302 may be made of a heat formable polymer that may be heated and bent into curvature and becomes rigid again when bent regions are cooled. Alternatively plate 302 may be made of a metal that may be bent around stationary forms into a desired shape.

Nine regions are labeled along plate 302, which are also labeled on brush 301 of FIG. 3 . Regions (a), (b), (c), (d) and (e) are regions of the backing plate 302 that correspond to straight regions (a), (b), (c), (d) and (e) of curb and gutter 105. Regions (0, (g), (h) and (j) are regions of the backing plate that will be bent to follow the rounded corners. In making brush 301 in this example backing plate 301 starting as a straight, flat plate, is formed at regions (0, (g), (h) and (j), and bent into the form shown in FIG. 3 . The process may involve attaching the straight plate to a bending fixture with or without heating apparatus. There are different ways known in the art to accomplish the bending, depending at least in part on the thickness and material of the plate.

FIG. 4B illustrates a bristle unit 401 with bristles 403 joined to an elastic and flexible backing 402, which may be easily formed to the shape of the heated and bent backing plate 302. Backing 402 may be natural or synthetic rubber, or a rubber-like polymer with suitable hardness and flexibility. In this example there an adhesive is added on the upper surface of flexible backing 402. Alternatively, adhesive may be added as the elastic backing with bristles is joined to rigid backing plate 302. In the process bristle unit 401 is joined to formed rigid plate 302 beginning at one end and proceeding along the full length until the assembled brush 301 results.

FIG. 5 is an elevation view of a broom head 500 in a stage of assembly, comprising a rigid backing plate 501, analogous to plate 302 of FIG. 4A, wherein plate 501 has been formed to have a particular curvature comprising three straight regions (a), (c), and (e), and two curved regions (b) and (d). Backing plate 501 may be a metal plate bent to the shape shown with use of bending fixtures, or it may be a polymer plate heated at the areas to be curved, and formed to shape, to become rigid again after cooling.

A strip 502 of a rubber-like backing 503 with bristles 504 is shown being assembled to the rigid backing plate 501. This strip with bristles is analogous to strip 401 of FIG. 4B, described above with reference to FIG. 4B. It will be apparent that no particular care has been taken in the drawing to represent the bristles, which are indicated as side-by-side lines orthogonal to strip 503.

A purpose of FIG. 5 is to represent a process of making a broom head such as broom head 500. A first step is to form the rigid backing plate 501. After the rigid backing plate is ready, a length of a strip 502, flexible with bristles, is cut to a length of the overall length of backing plate 501, or somewhat longer. Strip 502 is adhered to an underside of backing plate 501, starting from one end, in this example the end of straight region (a), by applying a suitable adhesive either to the underside of backing plate 501, to the upper side of bristle strip 502, or to both, and working the bristle strip onto the backing plate along the backing plate as shown in FIG. 5 .

In FIG. 5 the bristle strip 502 is shown as adhered to the underside of backing plate 501 from the one end of straight region (a), around curved region (b), and along straight region (c), and is yet to be adhered to curved region (d) and straight region (e). As the process continues the bristle strip will be adhered to the full length of backing plate 501, and if the bristle strip is longer than the backing plate, the bristle strip may be trimmed at the end of straight region (e).

Once the adhesion process is complete a pivoting connector like connector 203 may be added to the broom head 500 to enable attachment of a handle. This may be done in any of a variety of ways, depending at least in part on the materials of the broom head. In an alternative embodiment bristles may be implemented onto a heat formable backing plate, then the backing plate may be heated and bent to a desired shape. In this process plates of different lengths and widths may be provided, and bristles of different materials and density may be used. A user may select a backing plate of a desired size with a desired material and density of bristles, and cut the backing plate to a desired length, then selectively heat the cut plate in areas to be bent and bend the plate to a final curvature. Connector and handle may be added after the forming process.

The inventor is aware that in these exemplary processes, if the density of bristles in the bristle unit is the same along the full length, that when applying the bristle unit around a convex curve, such as region (d) in FIG. 5 , the bristle density in the finished brush will be substantially reduced, and when applying the bristle unit around a concave curve, such as region (b) of FIG. 5 , the bristle density will be substantially increased. This change in bristle density in most instances may not be a problem.

In an alternative embodiment, bristle units with elastic and flexible backing may be provided in different densities. Returning to FIG. 5 , it may be apparent that each region of backing plate 501 corresponds to (1) a straight region, (2) an outside curve, or (3) an inside curve. Region (a), for example is a straight region, region (b) is an inside curve, and region (d) is an outside curve, considering the underside of the backing plate where bristles are to be applied. Moreover, each straight region has a straight length, and each curves region has an arc length to the next straight region.

In this alternative embodiment there may be bristle units of different densities, which may be easily cut to desired length. One density may be a density desired for a finished brush surface. Call this the default density A. There may also be bristle units with a higher density B than the default density and of a lower density C than the default density.

In constructing a brush in the embodiment illustrated by FIG. 5 , a strip of a bristle unit with density A may cut to length for straight region (a), the length being the length of the straight region (a). This first strip may be joined to rigid backing plate 501 along region (a). A strip of bristle unit with density C with a length equal to the arc length of curved region (b) may then be cut and placed and adhered to the curved inside of backing plate 501 around the arc of region (b). In this application the curvature results in and increase in bristle density at the brush surface. If the bristle densities are controlled the result is a common bristle density at the brush surface for both the straight and the curved region. At an outside curve like region (d) a strip of the arc length of region (d) is used of the density B. The result is again a brush surface of a common density, or close to it. In this manner brushes of complex different shapes may be formed with the brush surfaces having a relatively common bristle density.

It will be apparent to the skilled person that the embodiments described are each and all exemplary and not limiting to the scope of the invention. Brushes of many widths and lengths and shapes may be provided in different bristle density and stiffness. Moreover, connection mechanisms may be provided for brushes in embodiment of the invention at different positions and in different numbers on different brushes, and handles of a variety of lengths, materials and shapes may be provided. There are similarly a variety of materials that may be suitable for the rigid backs of brushes, and for flexible backing of bristle units. A variety of adhesives may be used in assembly. The scope of the inventio is limited only by claims in a subsequent application. 

1. A shaped broom, comprising: a shaped rigid backing plate having a rectangular cross section with a width and a thickness, an overall length, an upper surface and an undersurface, the backing plate having two straight regions connected by a curved region; a bristle unit comprising an elastic and flexible backing having a rectangular cross section with a width the same as the width of the shaped rigid backing plate, an overall length the same as the overall length of the shaped rigid backing plate, an upper surface and an undersurface, with bristles extending orthogonally from all of the undersurface of the elastic and flexible backing of the bristle unit, providing a brushing surface at the end of the bristles away from the backing plate; and a handle connected by a connector mechanism to a point on the upper surface of the shaped rigid backing plate; wherein the upper surface of the bristle unit is joined to the undersurface of the backing plate by an adhesive along the full length of the undersurface of the backing plate.
 2. The shaped broom of claim 1 wherein the shaped rigid backing plate has three straight regions with a first and a second of the straight regions connected by a first curved region and the second and a third of the straight regions connected by a second curved region, the first curved region curving in one direction and the second curved region curving in an opposite direction.
 3. The shaped broom of claim 1 wherein the shaped rigid backing plate is formed from a straight plate of polymer.
 4. The shaped broom of claim 1 wherein the shaped rigid backing plate is formed from a straight plate of metal bent at regions to be curved.
 5. The shaped broom of claim 1 wherein the connector mechanism is adjustable to vary the angle of extension of the connected handle relative to the backing plate.
 6. A method for making a broom having a length and a width with a lengthwise curved shape, comprising: preparing a backing plate of the length and width with an upper surface and a lower surface; adding bristles to the undersurface of the backing plate; and forming the plate to the curved shape.
 7. The method of claim 6 wherein the backing plate is a heat-formable polymer, comprising heating the backing plate at specific regions, forming the plate to the curved shape and cooling the plate to be rigid again.
 8. The method of claim 6 wherein the backing plate is metal, comprising bending the metal backing plate at specific regions around bending fixtures.
 9. The method of claim 6 comprising: providing a bristle assembly with bristles extending orthogonally from an underside of the flexible, rubber-like material having the width and length of the backing plate; bending the backing plate to the lengthwise curved shape; and joining the bristle assembly to the underside of the backing plate by a suitable adhesive.
 10. The method of claim 9 wherein bristle assemblies of different bristle density are provided, comprising joining bristle assemblies of different density to different regions of the underside of the backing plate.
 11. The method of claim 6 further comprising joining a handle connector to the upper surface of the backing plate.
 12. The method of claim 11 further comprising connecting a handle to the backing plate by the handle connector.
 13. A shaped broom, comprising: a shaped rigid backing plate having a rectangular cross section with a width and a thickness, an overall length, an upper surface and an undersurface, the backing plate having first and second straight regions connected by a curved region; a first straight brush having a rigid base fastened to the undersurface of the shaped rigid backing plate along the first straight region by screw fasteners; a second straight brush having a rigid base fastened to the undersurface of the shaped rigid backing plate along the second straight region by screw fasteners; and a handle connected by a connector mechanism to a point on the upper surface of the shaped rigid backing plate. 